Tobacco with flavor enhancer

ABSTRACT

This disclosure is directed to a tobacco flavor enhancer from the reaction of valine with a sugar, other hydroxycarbonyl compound, or dicarbonyl compound. The reagents are heated in the presence of a solvent, optionally including a catalyst in the form of a flavanoid or hydroxyacid. The reaction mixture can be used directly in tobacco compositions, or can be stripped, and either or both the volatile and nonvolatile portion can be used in tobacco compositions.

, United States Patent [191 Warfield et a1.

TOBACCO WITH FLAVOR ENHANCER Liggett & Myers Incorporated, Durham, NC.

Filed: Mar. 7, 1972 Appl. No.: 232,526

Assignee:

U.S. Cl 131/17 R; 131/144; 260/209 R lnt. Cl. A24B 03/12; A24B 15/04Field of Search 260/209 R, 210 R, 21 1 R,

260/21l.5 R; 131/2, 17'R,144

References Cited UNITED STATES PATENTS 6/1955 Ruskins 260/21 1.5 R11/1956 King 260/21 1.5 R

[ Nov. 18, 1975 2,785.152 3/1957 Jonas 260/21l.5 R 2,805,219 9/1957Kagan et al..... 260/211 R 3,089,869 5/1963 Mauvernay 260/21 1.5 R3,304.184 2/1967 Wiseblatt et a1. 131/144 UX 3,722.516 3/1973 Suwa eta1. 131/144 X Primary Examiner-Melvin D. Rein Attorney, Agent, orFirm-Kenyon & Kenyon [57] ABSTRACT This disclosure is directed to atobacco flavor enhancer from the reaction of valine with a sugar, otherhydroxycarbonyl compound, or dicarbonyl compound. The reagents areheated in the presence of a solvent, optionally including a catalyst inthe form of a flavanoid or hydroxyacid. The reaction mixture can be useddirectly in tobacco compositions, or can be stripped, and either or boththe volatile and nonvolatile portion can be used in tobaccocompositions.

l4 (Jaims, No Drawings 1 TOBACCO WITH F'LAvoR ENHANCER I BACKGROUNDOFTHE INVENTION Numerous workers have investigated the reaction betweenamino acids and carbonyl compounds or sugars. This reaction is known asnonenzymatic browning and has been studied largely because of theultimate production of brown pigments in foods. An intermediate or sidereaction results in the production of volatile materials and certainless volatile'residues which have not been as extensively studied.However, it has been appreciated that these materials produceinteresting flavors and aromas.

The production, from amino acids and carbonyl compounds or sugars, ofsubst ances with desirable flavors and aromas, and the methods of usingthese substances, have raised several problems. For example, the flavorsand aromas produced may not be desirable, or desirable products may bemasked by the presence of other products. In addition, desirableproducts may be destroyed if maintained at elevated temperatures or uponreaction with other components. Furthermore, important differences mayexist in the suitability of the final product depending on theparticular amino acid used in the procedure.

Japanese Patent No. 9,239/71 discloses the preparation of specificcondensates of sugars with amino acids, which are added to tobaccoproducts. As the tobacco is smoked the condensates are thermallydecomposed and a fragrance is released.

It is an object of this invention to provide an improved method for thereaction of amino acids and sugars or other carbonyl compounds. Afurther object is the production of useful substances from the reactionof an amino acid, preferably valine, and a sugar or carbonyl compound,to provide tobacco compositions incorporating such substances. These andother objects are set forth, in great detail in the accompanyingdetailed specification.

SUMMARY OF THE INVENTION This invention is directed to a tobaccocomposition cifically it relates to the reaction of an amino acid with asugar or carbonyl compound at an elevated temperature in the presence ofa solvent. The reaction may be carried out with or without the inclusionof a substance acting as a catalyst, which has the effect of enhancingthe aroma and flavor of the tobacco to which the mixture is applied. I

The amino acid employed in the process of this invention is primarilyvaline, but mixtures of amino acids such as those derived by hydrolysisof proteins with a high valine content may also be used. Either opticalisomer of valine is suitable in this invention. V

The reagent with which the amino acid is reacted in the process of thisinvention may be a sugar or other carbonyl compound. Preferred sugarsare pentoses such as xylose, and hexoses such as glucose or fructose.Disaccharides such as maltose, or higher polysaccharides such asrafflnose may be used, but reducing sugars are preferred due to theshorter times and lower temperatures necessary for, running thereactions. Other carbonyl compounds which may be used in place of sugarsare, for example, hydroxyketones, such asdihy- 2 droxyacetone, ordicarbonyl compounds such as pyruvaldehyde.

The catalyst used-in the method of the invention may be a flavanoid,such as quercetin or rutin, or a hydroxyacid,.such as ascorbic acid.

The solvent used for carrying out the reactions specified according tothis invention may be any convenient liquid, such as polyhydroxylicsolvents, mineral or vegetable oils, or water. However, polyhydroxylicsolvents such as glycerol or propylene glycol are preferred, since theirboiling points are in the temperature range useful in the method of theinvention, and they are compatible with existing methods of tobaccoprocessing.

In the method of this invention the amino acid and carbonyl compound areadded to the solvent, the catalyst added, and the mixture heated tolO0-200C (preferably l20200C) for 0.5 to 5 hours, depending on thecombination of materials used. A condenser may be employed, but is notalways necessary. The re-;

action is usually complete when bubbling ceases; The molar ratio ofamino acid tocarbonyl compound can be from about I 10.5-10, with a ratioof l:4-5 being optimum in most cases. The weight ratio of amino acid tothe solvent used may be about 111-200, but ratios 'of' 1110- arepreferred. Weight ratios of catalyst to amino acid may be 0-100 percent,but levels of 0.510 percent are preferred.

The preferred reaction temperature for reducing sugars, hydroxycarbonylcompounds or dicarbonyl com-' pounds is l50160. This range oftemperatures usually results in reaction times of 45 to 60- minutes.Higher temperatures tend to produce objectionable, burnt aromas, andlower temperatures produce inconveniently long reaction times. In thecase of nonreducing sugars, such as sucrose or rafflnose, reaction ratesare much lower, and higher temperatures, longer reaction times, or acombination of these must be employed.

The reaction mixtures prepared according to this invention are useful intobacco as such, or can be further treated by passing the solutionslowly through a steamjacketed column under vacuum, trapping thevolatile materials in cold traps, and collecting the'solution containingthe nonvolatiles separately. This is known as the stripping operation.

The volatile portion of the reaction mixture is useful in improving thefragrance of tobacco and tobacco products, and in reducing throatirritation.

The nonvolatile portion of the reaction mixture is useful especially inpoorer tobaccos or those which have been aged for shorter than normalperiods of time. The usefulness of this material derives principallyfrom its ability to reduce or mask the green-grassy taste associatedwith these tobaccos. Another property of the nonvolatile part of thereaction mixtures is the enhancement of desirable flavor notes of theparticular tobacco to which it is applied, while suppressing undesirableharsh, or irritating properties.

In most of the reaction mixtures prepared according to this invention,the stripping operation is not absolutely necessary, especially if someof the more volatile materials are allowed to escape during thereaction. Nearly all of the desirable properties produced during smokingtobacco products containing these mixtures are attributable to thenonvolatile portion.

In addition to stripping, the reaction mixture may be improved byextraction with an immiscible solvent,

3 such as ether, methyl isobutyl ketone, or isobutyl acetate. Thisextraction is usually done after the mixture has been diluted somewhatwith water, and may be carried out as either a batch or continuousprocess.

Much the same effect as extraction can be accom plished by subjectingthe total reaction mixture to dialysis, using regenerated cellulose, orother suitable membrane. This process removes all the low molecularweight materials, resulting in an aqueous solution of browning pigments,which may be isolated by evaporating the water. These pigments possessall of the desirable properties of the total reaction mixture whenapplied to tobacco at appropriate levels. Thus, according to the methodof this invention, it is possible to preferentially remove theundesirable intermediates, and add only those materials which aredesirable for tobacco products.

The above properties of the reaction mixtures are also applicable in thecase of reconstituted tobacco productsv Undesirable taste properties ofthese tobaccos are often encountered, which are related to the greentaste of poor tobaccos, or the papery taste of stem material. Theadditive has the effect of masking these undesirable tastes, reducingthroat irritation and sting, and enhancing natural tobacco taste.

In practice, the unstripped reaction mixture can be applied to tobaccoin an amount equivalent to about 0.001 to 2.0 percent, based on theamount of amino acid used at the beginning of the reaction and the 4 Thefollowing specific examples serve to illustrate the procedure used inpreparing the flavorants and flavor enhancers described in thisdisclosure.

5 EXAMPLE 1 A mixture of 1 g DL-valine, 7.2 g D-glucose, 100 mg rutinand 100 ml glycerol was heated to 160 for min. An odor of chocolate withburnt sugar and peanut undertones was noticed on cooling.

EXAMPLE II A mixture of 20 g L-valine. 2 g rutin, and 24 g D- glucosewas added to 200 ml glycerol and heated to 160 for 1 hour, using areflux condenser to prevent loss of volatiles. When cooling, the mixturewas passed slowly through a stripper which consisted of a steamheatedglass coil connected in series to a receiving flask, two liquidair-cooled traps, and a vacuum pump. The volatile materials stripped offin the coil were trapped, and then washed out of the traps with ether.After separating and reextracting the water present in the traps, thecombined ether solutions were dried over sodium sulfate, and a totalsolids determination showed that the volatiles weighed 470 mg.

The nonvolatile portion of the reaction, which included the glycolsolvent, had a slightodor of chocolate, and weighed 253 g.

The following additional samples (Table I) serve to illustrate thevariations of the invention that produce amount of solvent employed. Theexact percentage de- 30 useful flavorants and flavor enhancers.

TABLE 1 Ex. Wt. of Carbonyl Wt. Vol. Reaction No. Valine (g) Cmpd. WLtg)Catalyst (g) Solvent (ml) Conditions Aroma Description 111 1.0 D-Glucose1.5 Glycerol 7 160l45 min Parched corn with chocolate undertones.

IV 1.0 D-Glucose 1.5 Rutin 1.0 Glycerol 7 160/45 min Chocolate-like,with sharp parched corn notes.

V 1.0 D-Maltose 2.4 Glycerol 10 160l45 min Pleasant, mild-chocolate.

V1 1.0 D-Raffinose 1.2 Glycerol 10 155/80 min Weak chocolate.

Reaction incomplete.

V11 10 D-Sucrose 1.5 Rutin 0.1 Glycerol l0 155l80 min Chocolate,Reaction incomplete.

V111 1.0 D-Fructose 1.5 Glycerol 160l45 min Strong, full flavored,

chocolate; peanut-like note.

IX 1.0 Dihydroxy- 1.54 Glycerol 10 /60 min Fairly good chocolate.

acetone with sour green notes.

K 1.0 Pyruvaldehyde 4.1 Glycerol 10 150/60 min Sweet, pleasantchocolate.

Xl 10.0 D-Glucose 15.0 Rutin 0.1 Propylene 100 /60 min Fruitychocolate.

glycol X11 10.0 D-Glucose 15.0 Rutin 0.1 d-Sorbitol 120g l60l45 minPungent, acid-like.

Xlll 10.0 D-G|ucose 15.0 Quercetin 0.1 Glycerol 100 160l45 minFruity-green chocolate.

.XlV 10.0 D-Glucose 15.0 Ascorbic 0 1 Glycerol 100 160/45 min Pleasantgreen-chocolate.

Acid

30% Aqueous solution.

pends on the effect desired. The material which has been stripped ofvolatiles is also applied at these levels, but usually somewhat higherthan the unstripped material. The volatile portion which collects in thetraps during the stripping operation is useful at about 0.001 to 0.05percent, based on its total solids content, which is determined while inether solution.

The methods of applying these materials are known to those practiced inthe art, but basically consist of spraying or dipping, preferablytheformer. One very convenient method is the incorporation of thematerial into the casing formulation and applying during the customarycasing operation. Another method is to mix the material with ethanol orother suitable solvent and to incorporate into the top-dressing, whichis then applied in the normal manner.

EXAMPLE XV A mixture of 20 g DL-valine, 157 g D-glucose, 0.20 g rutinand 600 g glycerol was heated to 160 in an open reaction vessel, andmaintained at this temperature for 1 hour, with continuous stirring. Themixture, on cooling, was diluted with 500 ml water and extracted withthree 200 ml portions of ether. The aqueous-glycerol solution was heatedon a steam bath for 2 hours to remove remaining traces of ether. Theresulting solution had a specific gravity of 1.213. Dialysis of analiquot against distilled water, using regenerated cellulose tubing asthe semipermeable membrane, showed that 18.6 g of browning pigments werecontained in the total solution.

Specific examples ofincorporating the reaction products from the aboveexamples into tobacco products are as follows:

EXAMPLE XVI EXAMPLE XVII The volatile portion from Example II wasdiluted to 50 ml with 95% ethanol. A 0.1 ml aliquot of this solution wasdiluted to ml with 50% aqueous alcohol and sprayed onto 100 g of lowgrade Virginia tobacco. Cigarettes made from this tobacco had anaccented Virginia tobacco taste.

EXAMPLE XVIII A solution of 0.05 g of the nonvolatile (stripped) portionfrom Example II, in 1 ml of 50% aqueous alcohol, was sprayed onto 100 gof low grade Virginia tobacco. Cigarettes made from this tobaccoexhibited a reduction of the green-grassy taste noticed in the controlcigarettes. The mixture also produced a rounding of the flavor and amuch smoother smoke.

EXAMPLE XIX The procedure of Example XVIII was repeated using a lowgrade Burley tobacco. The cigarettes made from this tobacco displayed areduction in impact and sharpness when compared to a control, and thedesirable burley fragrance was enhanced.

EXAMPLE XX The procedure of Example XVIII was repeated usingreconstituted tobacco. The cigarettes prepared from this tobacco, whencompared to control cigarettes, had

a reduced oak-leaf taste, and a sweet, spice-like flavor.

EXAMPLE XXI The procedure of Example XX was repeated, except that asolution of 0.1 g of the nonvolatile portion in 1 ml 50% aqueous alcoholwas used. Cigarettes prepared from this tobacco exhibited enhancedtobacco taste, along with reduced throat irritation and mouthpepperiness.

EXAMPLE XXII A solution of 0.1 g of the mixture prepared as set forth inExample XI, in 2 ml 50% aqueous alcohol, was sprayed onto I00 g of acased and cut commercial blend of tobaccos and evaluated as in ExampleXVI. The smoke from cigarettes thus prepared showed a noticeablereduction in impact and amplitude, and a slight reduction in theoak-leaf taste associated with reconstituted tobacco. The flavor showedless pepperiness and was somewhat sour.

EXAMPLE xxm A solution of 0.1 g of the mixture prepared as set forth inExample XIV, in 2 ml 50% aqueous alcohol, was sprayed onto g of acommercial blend of tobaccos and evaluated as in Example XVI. Thecigarettes produced a slightly lower impact and amplitude of flavor thanthe untreated control, with an increase in sour-green notes.

EXAMPLE XXIV A solution of 12 mg of the pigments isolated as describedin Example XV, in 2 ml of a 50% aqueous alcohol solution, was sprayedonto 100 g of unflavored cut tobacco, and cigarettes preparedaccordingly. The smoke produced by these cigarettes was described by theflavor panel as having a lesser degree of harshness and irritation thana similarly prepared control, with better balance, and more sweet tasteand tobacco fragrance.

This invention has been described in terms of specific embodiments setforth in detail. Alternative embodiments will be apparent to thoseskilled in the art in view of this disclosure, and accordingly suchmodifications are to be contemplated within the spirit of the inventionas disclosed and claimed herein.

We claim:

1. A tobacco composition comprising tobacco and a minor amount of aflavor enhancer wherein the enhancer is a non-volatile solution ofbrowning pigments made by heating between about l20 200C 21 reactionmixture containing a solvent, valine and a carbonyl compound selectedfrom the group consisting of a sugar, dihydroxy acetone andpyruvaldehyde.

2. The composition of claim 1 wherein the solvent is selected from thegroup consisting of glycerol and propylene glycol.

3. The composition of claim 1 wherein the reaction mixture contains acatalyst.

4. The composition of claim 3 wherein the catalyst is selected from thegroup consisting of rutin, quercetin, and ascorbic acid.

5. A tobacco composition comprising tobacco and a minor amount ofaflavor enhancer; said enhancer comprising the browning pigmentsseparated from the reaction product of a mixture heated to between aboutC and 200C of a solvent, valine and a carbonyl compound selected fromthe group consisting of sugar, dihydroxy acetone and pyruvaldehyde.

6. The composition of claim 5 wherein the solvent is selected from thegroup consisting of glycerol and propylene glycol.

7. The composition of claim 5 which further comprises a catalyst.

8. The catalyst of claim 6 selected from the group consisting of rutin,guercitin and ascorbic acid.

9. The composition of claim 1 wherein the sugar is a pentose or hexose.

10. The composition of claim 5 wherein the sugar is a pentose or hexose.

11. The composition of claim 1 wherein the sugar is a reducing sugar.

12. The composition of claim 1 1 wherein the temperature is betweenabout l50C and 160C.

13. The composition of claim 5 wherein the sugar is a reducing sugar.

14. The composition of claim 13 wherein the temperature is between aboutC and l60C.

1. A TOBACCO COMPOSITION COMPRISING TOBACCO AND A MINOR AMOUNT OF AFLAVOR ENHANCER WHEREIN THE ENHANCER IS A NONVOLATILE SOLUTION OFBROWNING PIGMENTS MADE BY HEATING BETWEEN ABOUT 120* - 200*C A REACTIONMIXTURE CONTAINING A SOLVENT, VALINE AND A CARBONYL COMPOUND SELECTEDFROM THE GROUP CONSISTING OF A SUGAR, DIHYDROXY ACETONE ANDPYRUVALEHYDE.
 2. The composition of claim 1 wherein the solvent isselected from the group consisting of glycerol and propylene glycol. 3.The composition of claim 1 wherein the reaction mixture contains acatalyst.
 4. The composition of claim 3 wherein the catalyst is selectedfrom the group consisting of rutin, quercetin, and ascorbic acid.
 5. Atobacco composition comprising tobacco and a minor amount of a flavorenhancer; said enhancer comprising the browning pigments separated fromthe reaction product of a mixture heated to between about 120*C and200*C of a solvent, valine and a carbonyl compound selected from thegroup consisting of sugar, dihydroxy acetone and pyruvaldehyde.
 6. Thecomposition of claim 5 wherein the solvent is selected from the groupconsisting of glycerol and propylene glycol.
 7. The composition of claim5 which further comprises a catalyst.
 8. The catalyst of claim 6selected from the group consisting of rutin, guercitin and ascorbicacid.
 9. The composition of claim 1 wherein the sugar is a pentose orhexose.
 10. The composition of claim 5 wherein the sugar is a pentose orhexose.
 11. The composition of claim 1 wherein the sugar is a reducingsugar.
 12. The composition of claim 11 wherein the temperature isbetween about 150*C and 160*C.
 13. The composition of claim 5 whereinthe sugar is a reducing sugar.
 14. The composition of claim 13 whereinthe temperature is between about 150*C and 160*C.